Medical imaging is the fastest growing component of medical spending in the United States, growing twice as fast as total health care costs. Remarkably few studies have compared the effectiveness of expensive imaging technologies. Studies comparing diagnostic imaging tests must include not only an assessment of diagnostic accuracy, but also a range of outcomes including patient health, functional status, morbidity and mortality, immediate and long-term safety, and cost. However, extremely few studies have gone beyond an assessment of diagnostic accuracy, and only a handful of studies have used a randomized controlled trial design to compare patient outcomes across imaging techniques. Although this application does not focus on one of the clinical areas highlighted by the AHRQ, it addresses a very common condition, where there is limited scientific data to support the choice in the Emergency Department (ED) between computerized tomography (CT) - the most common test used for urolithiasis -- and ultrasonography - a less expensive test that entails no radiation. This will establish a model for comparisons of CT with other alternatives. Indeed, emergency department orders account for 41% of all CT scans ordered. Thus, the proposal is highly relevant to the goal of AHRQ to define how to use health care resources more effectively to improve patient health. The current application focuses on urolithiasis (urinary stone disease), a very common condition with a lifetime risk of 10-15%. Urolithiasis accounts for 1% of all ED visits, approximately 1.1 million visits annually to U.S. EDs. CT was introduced as an alternative to ultrasonography in 1995, and in the United States has been rapidly embraced as the gold standard for diagnostic imaging in patients with suspected urolithiasis. There are several reasons CT likely has replaced ultrasonography, including the speed of the examination, less skill required to perform or interpret studies (making it easier for radiology departments to provide this examination), excess CT capacity making it widely available, and greater reimbursement for CT compared with ultrasonography, resulting in financial incentives to use CT rather than ultrasonography. However, there are several reasons to question the widespread use of CT related to safety and cost. First, CT delivers substantial radiation doses to patients, and these doses are in the range where carcinogenesis has been documented. Second, computed tomography identifies many incidental findings that result in further testing, clinical follow up, and treatment that may be unnecessary. Lastly, CT is expensive and substantially increases the cost of care for urolithiasis. On the other hand, there are several potential advantages of using ultrasound as the initial imaging test in patients with suspected urinary stone disease, including its lack of radiation exposure (greater safety), widespread availability, fewer false positive diagnoses and lower cost. ED overcrowding is on the verge of crisis according to the Institute of Medicine, and one of the solutions identified is to increase the efficiency of patient care in the ED setting. If ultrasonography can be accurately performed in the ED (rather than radiology), then this will also substantially reduce the time for assessment and efficiency of patient management. Further, this overcrowding crisis is particularly dire at facilities that provide care for the underserved, where limited radiology resources further compound delays, and thus where ED-provided point of care ultrasound could have an even greater impact on patient throughput. We propose a multicenter, randomized controlled trial of ultrasonography compared with CT for the evaluation of patients with suspected urolithiasis. The study will be conducted at 10 large urban EDs, reflecting geographic, socioeconomic, racial and ethnic diversity, and will include academic medical centers as well as safety net hospitals. The patients will be randomized to one of three arms: 1) ultrasound in the ED, 2) ultrasound in radiology, or 3) CT in radiology. We will then collect precise and unbiased data on a comprehensive range of outcomes that will allow assessment of effectiveness, safety, accuracy and cost between patients randomized to one of the three groups. Taken together, these measures are intended to provide the basis for a valid comparison of imaging of patients with suspected urolithiasis seen in the ED. The results of this trial could lead to a change in clinical practice that is associated with both improved patient outcomes and reduced cost. Broad stakeholder involvement from within radiology, emergency medicine and several subspecialty communities has been sought to ensure the strategic completion of study aims and to help rapidly disseminate the results of the study into clinical practice. This will create a collaborative network of EDs willing to act as a laboratory for studying the comparative effectiveness of diagnostic testing. As a result, the proposed trial will demonstrate the feasibility of conducting RCT of imaging that incorporates measurements of outcomes that can be expanded to additional imaging tests in the future. PUBLIC HEALTH RELEVANCE: This study compares different imaging strategies for patients seen in large emergency departments with symptoms concerning for urolithiasis (kidney stones). The study proposes a multicenter, randomized controlled trial of ultrasonography compared with computed tomography for the evaluation of patients with suspected kidney stones. The study will enroll patients at 10 large urban Emergency Departments (ED) and patients will be randomized to one of three arms: 1) ultrasonography in the ED, 2) ultrasonography in radiology, or 3) computed tomography in radiology. The study will then collect precise and unbiased data on a comprehensive range of outcomes that will allow assessment of effectiveness, safety, accuracy and cost between patients randomized to one of the three groups. Taken together, these measures are intended to provide the basis for a valid comparison of imaging of patients with suspected urolithiasis seen in the ED. The results of this trial could lead to a change in clinical practice that is associated with both improved patient outcomes and reduced cost.